1911—Edinburgh, Scotland

Encyclopedia Britannica, in one of its most renowned editions, discusses several types of trombones, claiming there are six currently in use: “At present six trombones are more or less in use, viz. the alto trombone in F, the alto in E♭ (formerly in D), the tenor in B♭ (formerly in A), the bass in G, the bass in F (formerly in E), the bass in E♭ (formerly in D), and the contrabass in B♭.” The article also shows engravings of two somewhat unusual instruments: what it labels a double slide trombone (see upper image; public domain) and a contrabass trombone by Boosey & Co. (see lower image; public domain).**